18F-FDG PET/CT findings of radiographic lesions suggesting old healed tuberculosis

Abstract

Introduction : The presence of radiographic lesions suggesting old healed tuberculosis (TB) is one of the strongest risk factors for the subsequent development of active TB. We elucidated the metabolic activity of radiographic lesions suggesting old healed TB using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and compared the uptake with the results of the tuberculin skin test (TST) and interferon-γ release assay (IGRA). Methods: This cross-sectional study included 63 participants with radiographic lesions suggesting old healed TB and with available 18F-FDG PET/CT scans. The maximum standardized uptake value (SUVmax) was measured in the lesions, and the clinical characteristics and results of the TST and IGRA were analyzed. Results : The SUVmax in old healed TB was 1.5 or higher among nine (14.3%) participants. Age [adjusted odds ratio (aOR), 1.23

95% CI, 1.03-1.46], history of previous TB (aOR, 60.43

95% CI, 1.71-2131.65), and extent of the lesions (aOR, 1.34

95% CI, 1.02-1.75) were associated with higher SUVmax. The positive rates for the TST and IGRA were not different between groups with and without increased FDG uptake. Conclusions : Increased FDG uptake on 18F-FDG PET/CT was observed in a subset of patients with radiographic lesions suggesting old healed TB. The clinical meaning of the increased FDG uptake should be determined in future studies.